Iberis L.
Iberis is a genus of 27 species (40 according to Upson 1995 and Jäger & al. 2008) native to Europe and the Mediterranean region. Only one species, Iberis amara L., is native in Belgium while several others are cultivated as ornamentals (see Upson 1995 for an overview of the genus in cultivation in Europe). A peculiar form (cultivar?) of Iberis amara is sometimes included in wild flower-mixtures. It is a taller plant with a much larger inflorescence. Such plants are best referred to as var. coronaria (D. Don) Voss and have been confused with Iberis gibraltarica L. in Belgium (see below).
Iberis is a well-defined genus (zygomorphic flowers, often corymbose inflorescences, distally winged fruits, etc.) which limits are not contested (Al-Shehbaz 2010).
1. Small, shrubby evergreen perennial with decumbent stems, becoming woody at base === Iberis sempervirens
1. Annual with erect stems === 2
2. Inflorescence a raceme, elongating in fruit (native) === I. amara
2. Inflorescence a corymb, not elongating if fruit === 3
3. Petals white. Plant bristly hairy. Leaves (at least the lowermost) pinnatifid === I. odorata
3. Petals pink to purplish (sometimes white in cultivars). Plant glabrous. Leaves entire or at most shallowly toothed === I. umbellata
Additional aliens: Iberis pinnata L. (C and S-Eur., W-As., seed and grain alien). A record of Iberis gibraltarica from Feluy in 1973 (De Langhe 1976) turned out to be in error for I. amara var. coronaria (Verloove & Lambinon 2008).
References
Al-Shehbaz I.A. (2010) Iberis. In: Flora of North America Editorial Committee (eds.), Flora of North America, vol. 7. Oxford University Press, New York-Oxford: 563-564.
De Langhe J.E. (1976) Adventices nouvelles pour la flore belge. Bull. Soc. Roy. Bot. Belg. 109: 25-27.
Jäger E.J., Ebel F., Hanelt P. & Müller G. (eds.) (2008) Rothmaler Band 5. Exkursionsflora von Deutschland. Krautige Zier- und Nutzpflanzen. Springer Verlag, Berlin: 880 p.
Lambinon J., Delvosalle L., Duvigneaud J. (avec coll. Geerinck D., Lebeau J., Schumacker R. & Vannerom H.) (2004) Nouvelle Flore de la Belgique, du Grand-Duché de Luxembourg, du Nord de la France et des Régions voisines (Ptéridophytes et Spermatophytes). Cinquième édition. Jardin botanique national de Belgique, Meise: CXXX + 1167 p.
Pinto da Silva A.R. & Franco J.A. (1993) Iberis. In: Tutin T.G. & al. (eds.), Flora Europaea, vol. 1. (2nd ed.). Cambridge University Press, Cambridge: 390-393.
Upson T. (1995) Iberis. In: Cullen J. & al. (eds.), The European Garden Flora, vol. 4. Cambridge University Press, Cambridge: 158-159.
Verloove F. & Lambinon J. (2008) Neophytes in Belgium: corrections and adjustments. Syst. Geogr. Pl. 78: 63-79.
Villarrubia M. J. & Moreno M. (1992) Estudio comparado de Iberis odorata L. e I. pectinata Boiss. & Reut. (Cruciferae). Acta Bot. Malacitana 17: 127-133.